1. Field of the Invention
The present invention relates to a method of effectively producing a magnesium-based hydride that generates hydrogen when reacted with water.
2. Description of the Related Art
Like an alkali metal hydride, MgH2 (magnesium hydride) is an ionic bond hydride formed of the bonding of Mg2+ and H− and is generated by causing Mg (magnesium) to react with high pressure hydrogen under heating. The reaction for generating MgH2 is represented by the following formula (1).Mg+H2→MgH2  (1)
The powder of MgH2 is charcoal gray in color and stable in air. In water, however, it reacts with water and decomposes while releasing hydrogen. Hence, it is expected that MgH2 can be used as a hydrogen storage material that releases hydrogen by storing hydrogen in advance and by reacting with water as necessary. The reaction of MgH2 with water is represented by the following formula (2).MgH2+2H2O→Mg(OH)2+2H2  (2)
Japanese Patent Publication No. 4083786 discloses a method of effectively producing MgH2. The technique disclosed in Japanese Patent Publication No. 4083786 keeps a material powder including magnesium in the atmosphere of hydrogen gas and removes the coating from the surface of Mg by maintaining the temperature and pressure of hydrogen gas at temperature and pressure at which Mg and H2 is thermodynamically stable. Next, the temperature and pressure of hydrogen gas are maintained at temperature and pressure at which MgH2 is thermodynamically stable, to cause Mg to react with H2. This method enables high-yield production of MgH2.